Amortization Calculator

Generate a complete amortization schedule for any loan. See monthly principal and interest breakdown, remaining balance, and how extra payments accelerate payoff.

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Amortization Schedule (Yearly)

YearPaymentPrincipalInterestBalance

Understanding Amortization

Amortization is the process of spreading a loan into a series of fixed payments over time. Each payment covers both interest and principal, but the ratio between them shifts dramatically over the life of the loan. In the early years, most of your payment goes to interest; in the later years, most goes to principal.

The Amortization Formula

The standard amortization formula is:

Amortization Formula
M = P · r(1 + r)n (1 + r)n − 1
M = monthly payment  •  P = principal (loan amount)  •  r = monthly interest rate (annual ÷ 12)  •  n = total number of payments (years × 12)
This formula ensures each payment is the same amount while the principal-to-interest ratio shifts over time.

How Extra Payments Work

Extra payments go directly toward reducing the principal balance. Since interest is calculated on the remaining balance, every dollar of extra principal means slightly less interest on every future payment. Even small consistent extra payments can save tens of thousands of dollars and years off a 30-year mortgage.

For example, adding $200/month in extra payments to a $320,000 loan at 6.75% saves approximately $78,000 in interest and pays off the loan about 8 years early.

Yearly vs Monthly Amortization

The yearly schedule above summarizes totals for each year. In a monthly schedule, you can see the exact split of every single payment. Early in a 30-year mortgage at 6.75%, roughly 75% of each payment goes to interest. By the midpoint, it's close to 50/50. In the final years, over 95% of each payment reduces principal.

Types of Amortized Loans

Mortgages are the most common amortized loans, but the same principle applies to auto loans, student loans, and personal loans. Any loan with fixed periodic payments that pay off both principal and interest uses amortization.

Frequently Asked Questions

What does amortization mean?
Amortization is the process of paying off a debt through regular equal installments. Each payment covers interest and a portion of principal, with the proportion shifting toward principal over time.
Why do I pay more interest in the early years?
Interest is calculated on the remaining balance. Since your balance is highest at the start, the interest portion is largest. As you pay down principal, less interest accrues each month.
How much can I save with extra payments?
It depends on your loan size, rate, and how much extra you pay. As a rule of thumb, one extra payment per year on a 30-year mortgage can shave 4-5 years off the term.
Is it better to make extra payments or invest?
If your mortgage rate is higher than your expected investment return (after taxes), extra payments are better. If your rate is low and you can earn more investing, the math favors investing. However, the guaranteed "return" of debt reduction has value.

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